Force transfer system



Aug. 2, 1966 J. ADAMSK! FORCE TRANSFER SYSTEM 4 Sheets-Sheet 1 FiledDec. 6, 1965 INVENTOR. e/ZJM flfii" ATTORNEY Aug. 2, 1966 J. ADAMSKI3,263,515

FORCE TRANSFER SYSTEM Filed Dec. 6, 1963 4 SheetsSheet :3

INVENTOR.

W92 jaw/M BY 81 m. a. 21m

ATTORNEY Aug. 2, 1966 J. ADAMSKI 3,263,515

FORCE TRANSFER SYSTEM Filed Dec. 6, 1965 4 Sheets Sheet 5 iwlaww A T TORNEY Aug. 2, 1966 I J. ADAMSKI 3,263,515

FORCE TRANSFER SYSTEM Filed Dec. 1963 r 4 Sheets-Sheet 4 flf W ATTORNEYUnited States Patent FORCE TRANSFER SYSTEM Joseph Adamski, ManitouBeach, Mich, assignor to Dura Corporation, Oak Park, Mich., acorporation of Michigan Filed Dec. 6, 1963, Ser. No. 328,572 3 Claims.(Ci. 74105) This invention relates to power trains and force transfersystems in general and more particularly to new and novel means of usinga linear force applicator to obtain more effective and efficientactuation of a rotary member.

There are-numerous instances in which it is necessary or desirable touse a linear force applicator to obtain rotary or oscillatory movementof another member. Normally this is accomplished by connecting thelinear force applicator directly to the rotary member at a point thereonwhich is spaced from its rotary or pivotal axis. This, inturn, requiresthat the point of application move with the rotary member and there is aconsequent variance in the effective moment arm causing rotary movementas the linear force travels towards and away from the rotary axis of thedriven member.

It will be appreciated that the effectiveness of the linear force isminimized as it approaches the axis of the rotary member and iscompletely lost at the commonly known dead-center position where itpasses through the rotary axis. Accordingly, full rotary actuation by alinear force applicator normally requires some means, such as a flywheel, to carry the rotary member through the dead-center position. Forthis reason pivotal or rocker arm actuation of a rotary member isnormally limited to less than 180 to avoid such dead-center problems.However, the prob lem of lost power as the linear force approaches thedead center position still prevails.

In general, the linear force applicator is normally used to obtainpivotal or rocker arm movement of a rotary member only when the movementrequired is less than 180. Even such a half-cycle is limited to thoseinstances in which maximum power is required at the mid-cycle rotaryposition. Where maximum power is required to be applied at either orboth of the forward and return actuating positions, as in a rocker armarrangement for example, the effective use of the linear forceapplicator is limited to a travel are of about 90, beyond whichlimitation such linear force becomes progressively less effective upon arotary member to a zero factor at the dead center position previouslymentioned.

The operating mechanism of a folding top for convertible automotivevehicles provides a good example of the use of a linear-to-rotarytransfer device wherein considerable improvement is needed. Some suchinstallations require rotary movement of a top operating link, which isusually a rear side frame rail of the top structure, through an arcclose to, if not exceeding, 180. Furthermore, full power is needed tolift the top structure out of the storage well when erecting the top andoff the windshield header bar in retracting and collapsing the top forstorage. Suflicient power is also needed at both ends of the travel arcto hold the top structure erected and seated on the windshield headerbar as well as to hold the retracted top structure securely seated andstacked in the storage well.

Most folding tops for convertible vehicles are operated by hydraulicpower cylinders. Such linear force applicators are usually eitherpivotally mounted on the vehicle floor or trunnion mounted on a supportunder the rear side rail and are connected directly to such rear wideframe rail or a like member of the top operating structure. In general,different crank arm arrangements, variations in the interconnection ofoperative members, power trans- Patented August 2, I966 ice ferconnections and links and the like have been used to obtain betteroperational eificiency. However, few innovations have been suggested asregards the disposition of the power cylinder or other linear forceapplicator. The prime concern in locating the power cylinder or otherforce applicator has been to obtain tangential travel of the appliedforce relative to the rotary axis of the driven member of the operatingstructure. As a consequence, the changes have been mostly in operatingstructure and have included longer cylinders to obtain a greater stroke,have required undue space to swing the cylinders, and have resulted inthe exposure of operative parts, connecting arms, etc. which should notbe visible.

One of the better folding top operating mechanisms makes use of parallelor trapezium type of four-bar linkage wherein the rear frame rail andbalance links serve as crank arms and a power transfer link or likemember serves as a connecting link therebetween. Numerous advantages areobtained in such an arrangement but still further improvement isobtainable therein in the application of the teachings of this inventionthereto. For emphasis in this regard, reference will be made to thepower transfer device of this invention as applied to such use in thesubsequent discussion. However, it should be remembered that many otheruses of equal importance may be made of the device disclosed.

It is an object of this invention to provide a power train or transfersystem wherein a linear force applicator may be used to greateradvantage to obtain rotary motion of a driven member.

It is an object of this invention to provide a linear-torotary drivesystem wherein arcs of or more may be traversed by rotary memberswithout dead center problems or appreciable power losses.

It is an object of this invention to provide a linear-torotary drivepower train wherein power output of the rotary driven member may beeccentuated at end stroke positions and beyond the normal quadrantrestrictions.

It is an object of this invention to provide a compact and simpleoperative mechanism for the transportation of linear forces to rotaryactuating forces without minimization thereof and, in fact, greater andmore effective utilization of the available power for the task required.

More specifically, it is an object of this invention to utilize a simplefour-bar linkage system wherein one of the cranks is the rotary memberto be driven and a drive force applied through an extension of theconnecting link, between the customary driving and driven links, willobtain a leverage advantage and additional power in the course of rotaryactuation induced by a linear force applicator.

Other objects of this invention include providing a power transferdevice which is complete, simple and compact in arrangement, whereinmovement arm forces may be obtained beyond normal over-center positions,wherein controlled force variation is prevalent throughout the entireoperative cycle, and wherein the linear force applicator may be disposedessentially stationary.

These and other objects and advantages to be gained in the practice ofthis invention will be better understood and appreciated upon a readingof the following specification in regard to a preferred embodiment ofthe invention and having reference to the accompanying drawings wherein:

FIGURE 1 is a side view of a power transfer device incorporating theteachings of this invention.

FIGURE 2 is a plan view of the power transfer device shown in FIGURE 1 asseen in the plane of line 22 therein.

FIGURE 3 is a rear and partially cross-sectioned view of the powertransfer device shown by FIGURE 1 as seen 3 in the broken plane of line33 therein and looking in the direction of the arrows.

FIGURES 4-9 are schematic sketches of the force transfer device on theother drawing figures showing progressive positions of the componentsthereof and used for force analysis purposes.

FIGURES -12 are also schematic sketches of the force transfer device ofFIGURES 1-3 but are here used to show for force analysis of thedifferent and cumulative forces derived from the disclosed system.

FIGURE 13 is a partial schematic of a modified force transfer devicehaving the travel of the power actuator shown graphically thereon.

The power transfer device shown by the drawings includes a mountingbracket 10 having a base portion 12 of inverted channel cross-section.The side walls of the base are extended at one end to provide trunnionsupports 14 and 16 and a support plate 18 is disposed in a verticallyupright position over the base 12. A triangular plate 20 is secured tothe back of the base 12 and support plate 18 to provide verticalrigidity for the latter.

The linear force applicator is a power cylinder 22 of the hydraulicfluid type. The cylinder portion 24 is disposed between the trunnionsupports 14 and 16 and mounted on the trunnion support pins 26 and 28. Apiston rod 30 extends from the trunnion supported end of the cylinder inthe plane of the support plate 18.

An operative four-bar linkage 32 is provided on the mounting bracket 10.It includes a driven member 34 which serves as one of the cranks andmight be such as the rear frame side rai'l member of a foldingconvertible top structure.

Driven member 34 has a forked end 36 and is secured to the upperdisposed end of the support plate 18 by a pivot pin 38. The drivenmember is accordingly rotatable essentially in the plane of the supportplate.

A control link 40, which is actually a pair of links disposed inparallel spaced relation, has one end secured to the support plate 18 ona pivot pin 42. The control link rotates about the axis of the pivot pin42 in unison which the driven member 34 in a manner to be presentlydescribed.

A connecting link, 44, which may subsequently be referred to as a thrusttransfer or rocker link, is shown as a pair of parallel spaced linkssecured by a pivot pin 46 to the driven member 34 and having the otherends thereof secured by a pivot pin connection 48 to the extended end ofthe piston rod 30.

The control links have their extended ends connected by a pivot pin 50to the connecting links 44 intermediate the ends thereof. A spacer 52 isprovided between the parallel spaced connecting links 44 and a commonpivot pin 50 is used. It will also be noted that the control links 40are formed to include an offset 54 intermediate-their ends for moresuitable engagement with the support plate 18 and with the connectinglinks 44 disposed in different reference planes.

It will be appreciated that the effective length of the connecting link44, as such, is that portion of the links between the pivot pins 46 and50. The extended end 56 of the connecting link, have the lineal forceactuator connected thereto, causes it to also serve as a rocker or leveras fulcrumed on the control links 40.

Referring now to FIGURES 4-9:

In the schematic sketches only the mounting bracket 10, driven member34, control link 40 and connecting link 44 are specifically identified.The line of linear force application has been identified 22' forreference back to the use of the hydraulic power cylinder 22 for suchpurposes. In all other respects reference should be made to FIGURES 1-3for structural details mentioned in the subsequent discussion.

With the driven member 34 disposed as shown by FIG- URE 4, the line .oflinear force application 22' introduces an operative force into theoperative linkage through the end of the connecting links 44. This forceis, in part, a compressive thrust force which is transmitted through theconnecting link to the driven member 34 for rotary actuation thereofabout its fixed axis to the support plate 18.

At the same time, the control link 40 is similarly receptive of themoment arm force through the connecting link 44 for rotary actuationthereof about its fixed pivotal connection to the support plate 18.

In addition, the connecting link 44 itself is receptive of a moment armcomponent tending to induce counterclockwise rotation thereof about itspivotal connection to the end of the control link 40. This, in turn,introduces a tensioning component in the driven member 34 and a forcecomponent normal thereto which is additive to the first mentioned rotarydrive force and thereby provides accentuated rotary actuation of thedriven member 34.

Considering the application of force to the operative mechanism inanother manner, the connecting link 44 and control link 40 may beconsidered parts of a toggle link joint operative of the driven member34. If the applied force were at the pivotal connection of theconnecting link 44 and control link 40, a rotary drive, as shown by thearrows a and b, would normally result as the joint was spread and crankswere induced to move in a clockwies direction about their fixed pivotalaxes. With the applied force provided on an extended end of theconnecting link 44, a counter rotating force, as shown by the arrow 0,is introduced and a leverage accentuated rotary drive is introduced intothe driven member 34, as shown by the arrow d, in the further spread ofthe toggle link joint.

Reference of FIGURES 10-12 where the forces are shown separately willhelp to understand what happens a little better.

In FIGURE 10 the linear force 22' is shown to have a moment arm M-l withrespect to the link 40. The resultant force moment acts through theoperative linkage to rotate the driven link 34 in a clockwise directionthe same as if the moment arm was M-la.

FIGURE 11 shows the linear force 22 offset to the toggle joint pivot 50(of links 40 and 44) and identified as 22". At such point it causes thetoggle spreading force identified by the arrow TF; the link 40 beingfixed to the mounting bracket 10. This, in turn, produces a moment armM-2 with respect to the driven link 34 and another clockwise rotatingforce with respect thereto.

FIGURE 12 shows the linear force 22' as producing a moment arm M-3 withrespect to the short end 56 of the link 44. This is transposed to amoment arm M-3a at the longer end of link 44 and with respect to thetoggle spreading force TFa created by the rocker arm action of the link44. The moment arm M-3b results with respect to the driven link 34 and astill further clockwise rotating force is imposed thereon.

Returning now to the operative sequence following from the applicationof power to the driven link 34 through the link 44:

As the driven member 34 attains the radial position shown by FIGURE 5,the thrust force component through the thrust or connecting link 44 isgreater in that the line of linear force application 22' is in closeralignment with the thrust or connecting link. The application of greaterforce is also apparent in that the line of linear force application 22'is spaced further from the fixed pivotal connections of the drivenmember 34 and the control link 40 than in FIGURE 4 and the moment armforces will accordingly be greater.

the situation in the arrangement of FIGURE 4, and the counter rotatingmoment arm force is accordingly less.

It will be appreciated that while the rocker or leverage accentuatedrotary drive force is less between the linkage positions of FIGURES 4and 5, the thrust force through the link 44 has increased. This rockeror leverage drive force persists throughout the operation of the linkage(except in one instance which will be identified later) and may bevaried by different proportioning of the link or offset shapes thereof.Certain aspects of this invention in this regard will be furtherappreciated in the subsequent discussion and in the description of themodification shown by FIGURE 13.

Referring now to FIGURE 6, it will be noted that the line of linearforce application 22 is approaching alignment with the connecting link44. Referring back to FIGURES 4 and 5 and forward to FIGURE 7, it willbe appreciated that the connecting link 44 is actually rotating in aclockwise direction about its pivotal connection on the end of thecontrol link 40 rather than in the counterclockwise direction as mightbe expected by the application of the lineal force to the extended endthereof. This is due to the racing pivotal centers in the rotaryactuated members and the fact that the counter-rotational force isdissipated in the spreading of the toggle linkage as described earlier.

This additive aspect of the leverage induced spreading force on thetoggle linkage, and through to the driven member 32, continues until thelink 34 is aligned with the fixed pivot of the link 40. This closelyapproaches the position at which the linear force 22 comes intoalignment with the connecting link 44, as shown by FIG- URE 7, and canin fact by design be made to coincide therewith.

The length of the control link 40 and of the longer end of theconnecting link 44, that is the part between the links 44 and 32, ispurposely made greater than the distance between the fixed pivot point42 of the control link on the mounting bracket and the pivotalconnection 46 where the connecting link 44 joins the driven link 32.This is so the toggle link is never lost. The action is one of firstspreading and then collapsing the toggle link, as will be subsequentlyshown, with a leverage accentuated drive obtained in each instance.

Referring now to FIGURE 7, it will be noted that the line of linearforce application 22 has come into alignment with the connecting link44. In such a situation there is no leverage force applied through theconnecting link 44 but merely a rotary motion inducing thrust forceapplied therethrough. Although the rotary force moments are less thanheretofore or subsequently, due to the closer disposition of the line oflinear force application 22 to the pivotal axis of the driven member 34,this is of no consequence in an operating mechanism for foldingconvertible tops since, at such moment, the folding top mechanism isdisposed essentially in a vertical and balanced position where minimalforces are required to carry it over center.

FIGURE 8 shows that the leverage forces are again introduced through theconnecting link 44 as the driven member 34 passes beyond its over-centerposition. The rotary inducing thrust force through the connecting link44, and affecting the control link 40, prevails and a clockwise rotarymoment is induced in the connecting link 44 with a consequent leverageaccentuated rotary drive of the driven member 34 as shown by the arrow cand the additive component arrow d.

FIGURE 9 shows the end position of the driven member 34 and the forcesapplied thereto. It will be noted that these forces are considerablygreater than would otherwise be obtained in driving through the pivotalconnection of the control link 40 with the connecting link 44. In fact,this would be virtually impossible since it would require that the lineof linear force application 22' pass through the support plate 18 and soclose to the pivotal axis of the supporting member as to approach adead-center position. The leverage advantage obtained is most clearlyand emphatically emphasized in the arrangement of parts shown by FIGURE9.

Reference back to FIGURE 4, and in particular to the phantom lines 62and 64 on each side of the line 22, representing the linear forceapplicator, shows that the force applicator has a very small amount ofarcuate travel despite the broad sweeping arc which it imposes on thedriven member or link 34.

FIGURE 4 is also of further significance in appreciating that the lineof linear force application 22 should fall between the pivotalconnections 50 and 42, as shown by the dotted lines 66 and 68 andrepresented by the are 70, to obtain full advantage of the rocker armforce of link 44 and not have it work to the disadvantage of the system.Should the applied force be to the left of the pivot 50 the effect wouldbe to collapse rather than spread the toggle linkage. Should it be tothe right of the pivot 42 of link 40 on the mounting bracket it wouldobviously not obtain the desired rotational force on the control link.Preferably the force should be applied between the pivot point 38 of thelink 32 on the mounting bracket 10 and the pivot point 50. However, thebest balance between the leverage accentuated drive and thrust drivethrough the connecting link 44 is considered best obtained in thearrangement first mentioned.

A fuller appreciation of the application of greater power at the ends ofthe power stroke of the linear force applicator, and of the relativelysmall arc of pivotal movement required thereby to affect a large arcuatetravel of a driven member, will be had by reference to FIGURE 13.

Essentially the same linkage arrangement is provided as that which waspreviously described. Accordingly, like reference numerals are used toidentify like parts and to avoid the necessity of re-describing thebasic system. The principal change is in the use of a bell crankconnecting link 144 or, more properly described, a connecting linkhaving the rocker end 156 offset inwardly with respect to the four-barlinkage 132 disposed thereover.

The use of an inwardly or outwardly offset end on the connecting link 44is principally for positional advantage as regards the force applicatorand to obtain a straight line power stroke.

The swinging motion of the power cylinder 24 is practically nil in thearrangement shown; the lines 162 and 164 representing the outer disposedaxial positions assumed.

The are of the driven link 32 is identified by the numeral 101 and ithas been divided into several equal arcuate segments between its endpositions with the intermediate positions identified at 102-109,consecutively. The corresponding positions of the point of forceapplication to the end of the connecting link 144 are identified102-109, consecutively. These points are connected by a curve 111 whichshows the relatively straight line of travel of the piston rod 30.

It will be noted that the variations in the increments of travelrepresented 'by the points 102'-109 show a greater travel at thebeginning and ends of the power stroke than in the intermediate range.This clearly emphasizes that a greater activating force is applied tothe driven link 32 at the lift-off and set-down positions mostadvantageous in many applications and including the folding top usesmentioned previously.

It should be obvious that the linkage system disclosed lends itself tovarious uses and that different variations of the geometric patternsprovided by the pivot points, within the teachings set forth, willenable a wide variation of force potentials to be obtained.

It will be appreciated that the rever situation prevails in theapplication of a retracting force to the end of the connecting links 44or 144 and that the resultant forces are similarly but oppositelyapplied to the different components. Thus, as applied to a folding topfor convertible vehicles, the actuating forces at the ends of the arc ofrotary movement will in both instances be the greatest.

The force transfer linkage of this invention can be seen to producethree different force moments which work together to produce the desiredresult. All conflict between such force moments, as are present in othermechanisms of like kind, has been avoided. The compounding of the threeforce moments and their application with respect to the driven rotarymember 32 makes possible the use of a shorter stroke linear actuator anda linkage which is less massive and includes shorter operative links.The pivot geometry is extremely compact and the resultant mechanism ismost efiicient.

Without further discussion it should be obvious that numerous othervariations, modifications and combinations are conceivable and withinthe scope of this invention.

Although a preferred embodiment of this invention has been specificallyshown and described, with reference to a particular use, it will beappreciated that this has been done to illustrate the scope of thepresent invention and without intent to unnecessarily limit theinvention in any regard. Accordingly, such improvements, modificationsand alterations as are Within the spirit of this invention and are notspecifically excluded by the language of the hereinafter appended claimsare to be considered as inclusive thereunder.

I claim:

1. Power actuating linkage means comprising a mounting plate, a mainlever pivotally mounted adjacent one end to said plate, a control link,means pivotally mounting one end of the control link to said plate, alinear actuator, means pivotally mounting one portion of the linearactuator to said plate, a rocker link, means pivotally mounting one endof the rocker link to said main lever, means pivotally mounting theother end of the rocker link to another portion of the linear actuator,means pivotally mounting the other end of the control link to the rockerlink intermediate the pivotal connections at the ends of the rockerlink, the said pivotal connections being positioned such that the lineof linear force application from the linear actuator to the rocker linkis between the pivotal connections of the control link and the plate andthe control link and the rocker link during the high torque portion ofthe duty cycle of the power actuating mechanism.

2. The invention defined in claim 1 wherein the linear actuatorcomprises a cylinder and piston unit.

3. The invention defined in claim 1 wherein said high torque portion ofthe duty cycle is at one end of the travel of the power actuatingmechanism.

References Cited by the Examiner UNITED STATES PATENTS 1/1956 Hale296--l17 7/1963 Haganes 74l05

1. POWER ACTUATING LINKAGE MEANS COMPRISING A MOUNTING PLATE A MAINLEVER PIVOTALLY MOUNTED ADJACENT ONE END TO SAID PLATE, A CONTROL LINK,MEANS PIVOTALLY MOUNTING ONE END OF THE CONTROL LINK TO SAID PLATE, ALINEAR ACTUATOR, MEANS PIVOTALLY MOUNTING ONE PORTION OF THE LINEARACTUATOR TO SAID PLATE, A ROCKER LINK, MEANS PIVOTALLY MOUNTING ONE ENDOF THE ROCKER LINK TO SAID MAIN LEVER, MEANS PIVOTALLY MOUNTING THEOTHER END OF THE ROCKER LINK TO ANOTHER PORTION OF THE LINEAR ACTUATOR,MEANS PIVOTALLY MOUNTING THE OTHER END OF THE CONTROL LINK TO THE ROCKERLINK INTERMEDIATE THE PIVOTAL CONNECTIONS AT THE ENDS OF THE ROCKERLINK, THE SAID PIVOTAL CONNECTIONS BEING POSITIONED SUCH THAT THE LINEOF LINEAR FORCE APPLICATION FROM THE LINEAR ACTUATOR TO THE ROCKER LINKIS BETWEEN THE PIVOTAL CONNECTIONS OF THE CONTROL LINK AND THE PLATE ANDTHE CONTROL LINK AND THE ROCKER LINK DURING THE HIGH TORQUE PORTION OFTHE DUTY CYCLE OF THE POWER ACTUATING MECHANISM.